Hi,
No wonder I couldn't find them. When you're researching someone who died in 1791 or 1794, the research gets much more difficult. You have to find tax, land, will/probate, etc. records. Also remember that Mason county was established on Nov 5 1788 from Bourbon County. Records before that date will be located in Bourbon Co.
You'll find land records at the Mason County Clerk's office. Will/probate records are at the Mson County Circuit Court Clerk,
http://courts.ky.gov/courts/clerks/Pages/default.aspx?county....
Sometimes daughters aren't in their father's will because they were given their portion of his estate when they married.
The Mason County USGWEB site,
http://kykinfolk.com/mason/ has good information.
You can contact the Genealogical & Historical Research Library,
www.kygmc.org/ and ask if they have records prior to 1795. Successful Searching!